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berlyn_gw

The effects of River rock on the bottom of pond.

berlyn
12 years ago

I been ponding for 10+ years. I know every spring the dreaded algae bloom/green water/pea soup will come and will go. This year after seeing all the gunk on the rocks we decided it was time for a pond cleaning/degunking, divide water lilies and fertizile them. We did this in June, far after the yearly algae bloom had passed.

Now when we were setting up this pond 10 years ago, hubby & I debated about river rock on the bottom. He wanted it, liked the way it looked. "Natural" is what he called it. I was more skeptical after reading posts on this forum. He won & the river rock went it.

Back to this past June. We cleaned the river rock BUT did not remove them from the pond and do a "OCD thorough cleaning". Which we learned the later needs to be done if you choose to go the river rock route. Oh, did I mention the smell of the gunk. I felt like I was doing sewer work rather than pond!

After this "cleaning" I had nothing but green water ALL summer long! Which I posted a thread here--http://forums2.gardenweb.com/forums/load/ponds/msg1010235019818.html?10

I have racked my brain, picked through old threads on this forum. Asking myself, "Why this green water this time of year?" Telling myself, something is off balanced in the pond. Is it the drought, the 40+ days of 100'+ temps, too much sun, the fertilizer tabs. I even resorted to using an Algae Remover product, which only created more havoc on my plants & lilies and less surface coverage. I shaded the pond with patio umbrella's and/or landscaping material.

You name it, I tried it this summer!! But I still had green murky water. Hubby kept telling me, it was the plant fertilizer. I was skeptical once again, since that was June & it's now October.

Don't ask me what I was doing, but I once again did a partial water change and put my hand by the drain and stirred up all this "stuff". I checked the quilt batting in my biofilter thinking it would be filthy. It was not. Not even slightly dirty. Then I had a thought. Are those river rocks the root of my problem?

After 2 days of removing everything in my pond, including those river rocks. Getting a sunburn & every inch of my body aching, I am keeping my fingers crossed.

I did grab my phone & took some pics 1/2 way during this process.

Rocks after we removed them from pond. You can see all the leave particles on them.

{{gwi:235064}}

After I had to pry the water lilies from the rocks, the debris that I could get off, got cut off.

{{gwi:235065}}

The gunk left after removing the river rock. Keeping in mind we cleaned this pond out in June.

{{gwi:235066}}

The gunk that was removed with the river rocks.

{{gwi:235067}}

If you are debating on going with River Rocks or not on the bottom of your pond, sooner or later you will have problems! I won't even begin to tell what a mess and the smell!

On a positive note, the tropical lily I thought I lost. I did find back in June being smothered by a hardy was repotted and has bloomed all summer long. I have 2 more blooms coming up.

I will follow up with more pics.

Comments (18)

  • jalal
    12 years ago
    last modified: 9 years ago

    Thanks for posting pictures. I do not have rock in the bottom of my pond as it didn't make any sense to me. Having aquariums in the house knew that the aquarium syphon can't get all the crud out of gravel so in a pond rock would be a huge problem. Pond companies who install rock filled ponds claim the rock is needed for bacteria growth but anyone I've known who has gone this way has had nothing but headaches. The liner itself will get covered with the good bacteria. I do have rocks along the coping edge of my pond and wish that I had made that edge one rock depth instead of 10" deep--in some areas rocks are stacked three high to hide the liner and every spring I am moving rocks to get the crud out from underneath. Plus rocks in the pond would be very slippery it's bad enough on a liner pond.

  • hardin
    12 years ago
    last modified: 9 years ago

    I also debated on using river rock in the bottom of my pond and after reading the horror stories, I opted not too. I am glad I didn't. I have rocks on my shelf, like jalal, and it is messy enough with just those. Someday, I will have another pond and it will not have deep shelves.

    Here in Oklahoma, our summer was very hot and dry like yours. Surprisingly, my pond stayed crystal clear and algae free. Seems to me, that after the rocks were cleaned back in June, it knocked the water chemistry out of balance. Too much of one thing and not enough of another. It will most likely balance again given time. You might want to try some barley bales. They really seem to help my pond, but it does take some time. Good luck.

  • sandyl
    12 years ago
    last modified: 9 years ago

    My pond is always as clear as you see it in the picture, always.
    No river rock here either. Pond will be 12 years old next July. The pond liner will get just a little fine fuzzy algae on it during the early spring months but the fish love it and it's usually short lived. There are no rock except acouple brick o block that the plants sit on that have been in the pond for ever. The pump prefilter catches the few leaves that fall and I net the others out as needed and the biofilter gets everything eles. MY pond is about the least amount of work I have here on a 85 acre farm. During winter the whole pond gets covered up including the biofilter which I keeping running all winter, I drain the biofilter about the same time I stop feeding the fish and refill the pond to refill what I drained out and just cover up the whole pond with a heavy duty brown canves tarp that I bungie cord all the way around and down to the ground and just leave the pump & biofilter running. I know most people would say no need to leave the biofilter up and running during winter, as it's not doing any biofiltering,and I understand that, but it's keeping the water moving in the pond and bio filter and I don't have to store the 100 gal tank and spring start up is just a matter of removing the tarp and i'm ready to go. The winter temps have been down to -05 degrees and pond and bio didn't freeze at all during the winter. I cut down all the plants to the top of their pots and leave them where they are and cover them up also during winter. The roses in their posts will be moved up next to the house for winter pretection.

    {{gwi:199568}}

  • meyermike_1micha
    12 years ago
    last modified: 9 years ago

    Please tell me. where do you get that heavy tarp?

    I love that idea and even the fish survive, right?

    Love it love it!

    Do you keep that falls going too?

    Thank you so much

  • adriennemb2
    12 years ago
    last modified: 9 years ago

    What I want to know is why, oh why, can't someone manufacture a good quality heavy mil pond liner with a
    coloured and textured faux rock photofinish? Instant best seller!

  • lsst
    12 years ago
    last modified: 9 years ago

    adriennemb,
    A big box store did until about 5 years ago.
    I was building my pond at the time and it had been discontinued.

  • waterbug_guy
    12 years ago
    last modified: 9 years ago

    {{gwi:235068}}
    4' deep on the right side of the picture.

    Tons of people in the world say rocks help keep water clear. Tons of people in the world say rocks are the cause of all problems. Lots of opinions, little data. The causes of green water are complex and most people really don't want to get into it. The simple solution is a properly installed UV filter.

    I've never really understood the debate. Rocks don't create muck. You'd have the same amount with or without rocks. Cleaning should be the issue. Rocks just get the blame.

    It's harder to clean a pond with loose rocks. Is that the real debate?

    The pond in the picture above is mortared in place rock. That makes it as easy to vacuum as bare liner, plus I enjoy seeing the rocks so I'm happier to vacuum.

    Here's a new pond with mortared rocks.
    {{gwi:185450}}

    And after several months.
    {{gwi:197869}}
    So you can have it both ways, if you want.

    BTW, the ponds in the pictures had no filter of any kind other than streams.

  • berlyn
    Original Author
    12 years ago
    last modified: 9 years ago

    Here are some pics of my pond over the years I had river rocks and no problems. As you can see it was always crystal clear. I don't know what caused the problem of green water this year after 10+ years. Was it one particular thing or a combo of several. My small pond has river rock and has been crystal clear all summer long.

    Here are pic of the big pond after a couple years of installation.
    {{gwi:235069}}

    I have reworked the bog earlier this year.
    {{gwi:235070}}

    {{gwi:235071}}

    I will post some pics of the pond in a couple of days.Which is still crystal clear. Moved my koi back in yesterday. I also want to show others the effects of using algae/green water remover chemicals on my water lilies.

  • adriennemb2
    12 years ago
    last modified: 9 years ago

    waterbug, I definitely like that look of the mortared-in rock, especially coupled with the idea of only doing a circumscribed section as shown in the first photo. Imagine being able to see the stealth black goldfish at last! I just don't know how long it would hold up to the extreme temperatures here in the north. What chemicals might be released into the water if and when the mortar fails, do you know?

  • hardin
    12 years ago
    last modified: 9 years ago

    If the rocks are mortared, it probably works because nothing is trapped underneath, so that has to help with cleaning.

    To Berlyn, I'd love to have more information on your bog and the set-up. Pretty pond too.

  • sandyl
    12 years ago
    last modified: 9 years ago

    Posted by meyermike_1micha 5 (mikerno_1@yahoo.com) on Wed, Oct 19, 11 at 19:39

    Please tell me. where do you get that heavy tarp? Ordered them from Tarpsplus.com
    I love that idea and even the fish survive, right?> Fish were fine all winter.

    Love it love it!

    Do you keep that falls going too? Yes, ran all winter, worked great for me.

    Thank you so much

  • waterbug_guy
    12 years ago
    last modified: 9 years ago

    adriennemb, mortar on the bottom of the pond would hold up as long as anywhere else assuming your pond doesn't freeze solid. Cement isn't affected by cold temps, only ice. It doesn't release chemicals at least at any levels any reasonable person would be concerned about.

    In a freezing climate you do have to design for the top foot or so, the depth you expect ice. You have all the normal options, bare liner, dry stacked rock, etc. It you want to cover the liner my suggestion is to make cap rocks out of mortar. These can be flipped out of the pond in the fall if you like or left in the pond. Since they just hang there any ice behind them push them up a bit but no harm.

    {{gwi:235072}}

    The premixed mortars of today don't really fail, at least in our lifetimes. If you kept your pond in the acid range, say 6 pH or less, the acid would attack the cement and slowly dissolve it. Cement makes a poor pH buffer so you probably wouldn't be able to measure any raise in pH using normal pH tests. And in 6 pH and less the life of the mortar would be reduced to maybe the 20 to 30 year range. If the pond is in the 8 pH and above range there is very little affect on cement and you can expect it to last in the 50 to 100 year range. I got this info from studies of concrete water and sewer pipes. Here's a link to my web page on effects of cement in a pond.

  • adriennemb2
    12 years ago
    last modified: 9 years ago

    Thank you, waterbug guy. The link was very informative, gave me lots to think about for a newer, deeper pond and stream.

  • o2nmyhair
    7 years ago

    I have a 3000 gal new pond, PH today is 8.4, algae bloom going on. I am puzzled because tap water tests at 7.4. I have gravel in the bottom, large round baseball size pond rocks on tiers and shale rock for the flat support rocks, Any idea what can be causing the high PH?

  • chas045
    7 years ago

    A pH of 8.4 is not high; it is fine. Your rock could be the difference. However, it could just be the difference with water from your closed pipes vs open pond. Check your pH in the morning and afternoon and see if there is a big difference. That would indicate that you are having almost no effect from rocks. In any case it doesn't matter. Start a new thread about the algae.

  • o2nmyhair
    7 years ago

    Thank you so much Chas,,, appreciate the input very much, so I wont worry too much about the PH. This morning it was 8.3, so no swing so far.

  • ademink
    7 years ago

    The parameter to watch is KH. You want to make sure it is sufficient so you don't have a crash or high and low swings. The most important thing about pH isn't the number...but the stability. One thing to keep an eye on...Algae affects your oxygen in the pond at night. It makes oxygen during the day and uses it at night. Make sure you have sufficient oxygenation.